Hoesaeng-san is known to be effective for treating diarrhea and vomiting. However the therapeutic mechanism of Hoesaeng-san is still not well understood. The aim of the present study was to demonstrate the effects of Hoesaeng-san ethanol extract (HSSEE) on the expression of pro-inflammatory cytokines, as well as to elucidate its mechanism of action in the human mast cell line (HMC-1). Mast Cell were stimulated with phorbol 12-myristate 13-acetate (PMA) plus A23187 in the presence or absence of HSSEE. To study the possible effects of HSSEE, ELISA, RT-PCR, Western blot analysis were used in this study. HSSEE significantly inhibited the PMA plus A23187-induction of inflammatory cytokines such as tumor necrosis factor (TNF)-${alpha}$, interleukin (IL)-6 and IL-8. In activated HMC-1 cells, phosphorylation of extra-signal response kinase (ERK) 1/2 and c-jun n-terminal kinase (JNK)1/2 decreased after treatment with HSSEE. Moreover HSSEE inhibited PMA plus A23187-induced nuclear factor (NF)-${kappa}B$ activation and $I{kappa}B$ degradation. HSSEE suppressed the expression of TNF-${alpha}$, IL-6, IL-8 through a decrease in the ERK 1/2 and JNK 1/2, as well as activation of NF-${kappa}B$. These results indicated that HSSEE exerted a regulatory effect on inflammatory reactions mediated by mast cells.